Gardiner’s four-year old son, Henry, died in 2008 after suffering a seizure during sleep, a phenomenon referred to as Sudden Unexpected Death in Epilepsy (SUDEP). He was an otherwise healthy boy until his diagnosis of epilepsy, only 5 weeks before his sudden death.

Gardiner has a background in nursing and public health. She has worked as an emergency room nurse at Grady Memorial Hospital in Atlanta and as an international health policy advisor for CARE. More recently, she has been involved with local primary health care in Washington, DC. She chaired the board of the Washington Free Clinic and is currently a director of Whitman-Walker Health, Washington's preeminent HIV/AIDS and LGBT health center. Gardiner also serves on the Council of Public Representatives, an advisory group that reports to the Director of the National Institutes of Health (NIH).

Gardiner received her bachelor's degree in nursing from the University of Virginia and a Masters of Public Health from Emory University.

Gardiner and her husband, Nick, also own an organic fruit and vegetable farm in Virginia. They live in Washington, DC with their children Jack, Phoebe and Thomas.

CURE is a non-profit organization founded by mothers of children with epilepsy who joined forces to spearhead the search for a cure.